Design and analysis of laser-cut based moment resisting passing-through I-beam-to-CHS column joints

Abstract

Conventional circular hollow section (CHS) connections are often prone to severe local distortion of the CHS column surface, premature flange fractures and demand excessive welding quantity due to much-needed local stiffeners, gusset plates or the direct welding technique. This results in an unavoidable complexity, which leads to a possible economic disadvantage. This paper proposes an innovative I-beam-to-CHS-column "passing-through" connection, which avoids the foretold drawbacks and increases the structural performance of these joints. The moment-resisting connection studied in this article was developed during the research project LASTEICON. It consists of primary beams connected to an I-beam passing through the CHS column through slots obtained via Laser Cutting Technology. The characterization of the ultimate resistance of the proposed connection under symmetrical and antisymmetrical loading conditions in bending is studied in detail. This is performed through a parametric study based on finite element (FE) models, which are primarily validated through an experimental campaign. Encouraging agreements obtained between the numerical and experimental results in terms of joint stiffness as well as joint resistance are presented. Moreover, different failure modes are identified and further characterized by developing comprehensive guidelines to design the proposed connection. Analytical calculations for several case studies are performed following the proposed design procedure and the results are compared with numerical as well as experimental results. Promising agreement is achieved, therefore confirming its practical implementation. Ultimately, the "passing-through" connections are compared with conventional (direct weld) joints to highlight the former's advantages from a structural perspective.